Hollow walled folding boxes



' July 7, 1959 Q M. 1. WILLIAMSON 2,893,620

nonmw WALLED FOLDING BOXES Filed Oct. so. 195: i 3 Sheets-Sheet 1 i M ii 1 I I I a I I Lllip A- l l INVENTOR. Marshall I Williamson BY PM 5. M

ATTORNEY July-7, 1959 I M. (I. WILLIAMSON 2,893,620

HOLLOW WALLED FOLDING BOXES Filed Oct. 30, 1953 s Sheets-Sheet 2 JNVENTOR. Mars/ml! 1 Williamson ATTORNEY July 7,1959 M. l. WILLIAMSON HOLLOW WALLED FOLDING BOXES 5 Sheets-Sheet 3 Filed Oct. 30, 1953 INVENTOR. Marshall Williamson BY I'M '6. W

ATTORNEY United States Patent HOLLOW WALLED FOLDING BOXES Marshall I. Williamson, New Haven, Conn.

Application October 30, 1953, Serial No. 389,363

3 Claims. (31. 229-34 I This invention relates to the art of constructing boxes, cartons, trays, or other receptacles, hereinafter collectively referred to as boxes or folding boxes, made from paperboard, corrugated board, or other foldable sheet material. 7

This invention has particular reference to a method of calculating and delineating blanks of folding boxes having hollow walls of substantially triangular cross-section.

Hollow Walled boxes must meet exacting specifications with regard to appearance and strength. The most .important structural detail in this connection is the construction of the box corners, since it determines not only the neatness of appearance, but also the resistance of the box to deformation.

Folding boxes having hollow walls of triangular crosssection are principally produced in two styles, glued or unglued.

The unglued style of box is assembled entirely by folding and tucking-in of panels and flaps, and the strength and rigidity of the box is the result of proper engagement and abutment of panels and flaps.

In boxes of the glued style certain flaps and panels are secured together in the process of prefolding the blank to produce a flat collapsed structure which can readily be expanded into hollow box form. Instead of adhesive, equivalent securing means, such as staples, may be employed, and the references in this specification to glued boxes apply equally to blanks pre-assembled by staples, stitches, rivets and similar securing means. Nevertheless, for reasons of simplicity it will be sufiicient to make reference to the pre-secured boxes as glued-style boxes.

Glued boxes ofifer the advantage of simplified erection of the preglued blank into hollow box form, since the side wall assemblies and the end wall assemblies are connected at the corners, so that erection of one assembly automatically leads to partial erection of the other.

My prior Patent 2,522,325 of September 12, 1950 discloses and claims, among other details, a particularly advantageous and strong corner construction for hollow walled folding boxes having walls of substantially triangular cross-section. The corner construction includes a plurality of panels integral with the inner panel and with the outer panel of a hollow wall, for example, a side wall, the characteristic feature of the arrangement being, that the panel assembly which originally forms a continuation of the hollow side wall can be folded to extend in a new direction, at an angle to the direction it originally assumed, to furnish support for a further box wall, for example, an end wall, which extends at an angle to the side wall.

It is a peculiar characteristic of hollow walled boxes that a blank for a nonglued box cannot be assembled properly if flaps and panels are adhered together, as in a glued style box. A reason for this is the rather complex articulation, folding, and arrangement of the box corner assemblies.

1 This invention is concerned with certain improvements 2,893,620 Patented July 7, 1959 shaped corners, if the further requirement of predeter-' mined slope angles also has to be met.

The matter is rendered even more complicated, if the slope of the end walls differs from the slope of the side walls. For reasons of appearance the slope of the end walls, for example, is frequently made less steep or steeper than the slope of the side walls.

If the various fold lines and angles at the corner of the blank are not accurately laid out in the blank, an unsightly corner results in which, for example, gaps show between overlying panels, or dimples are formed on certain panels by reason of internal stresses to which the glue areas are subjected. Such defects are objectionable in a box, which, to a large extent, is a display box.

The invention solves these dificulties and makes it possible to predetermine the proper angular direction and length of the various critical fold lines and cut edges as well as the accurate size of panels at the corners in such a way that it is unnecessary to resort to tedious, uncertain, cut-and-try methods.

The invention permits the accurate layout of the blank to be determined on the drawing board and assures that a blank laid out according to the invention will produce an accurately shaped box presenting no problems during the gluing and setting up procedures.

.The advantages of the invention will appear more fully from the detailed description which follows, accompanied by drawings showing, for the purpose of illustration, a representative embodiment of the invention. The invention also consists in certain new and original features of construction and combination of elements hereinafter set forth and claimed.

Although the characteristic features of this invention which are believed to be novel will be particularly pointed out in the claims appended thereto, the invention itself, its objects and advantages, and the manner in which it may be carried out, can be better understood by referring to the following description taken in connection with the accompanying drawings in which:

Figure 1 is a plan view of a flat cut and scored box blank incorporating the present invention;

Figure 2 shows the blank of Figure 1 after a first compound folding operation accompanied by a gluing oper-' ation;

Figure 3 is a plan view of the blank of Figure 2 after a further folding and optional gluing operation, resulting in a flat collapsed structure ready for expansion into hollow box form;

Figure 4 is a perspective View of the blank of Figure 3 in the process of erection into hollow box form;

Figure 5 is a perspective view of the completed box.

Figure 6 is an end view, partly in section, of the box of Figure 5, a section being taken on plane 66-6 of Figure 5, the end bottom flap being shown upright, before folding and tucking-in;

Figure 7 is a cross section of the end wall; and

Figure 8 is a cross section of the side wall.

In the following description and in the claims, various details will be identified by specific names for convenience. These names, however, are intended to be generic in their application. Corresponding reference characters.

3 refer to corresponding parts in the several figures of the raw ngs- The drawings accompanying, and forming part of, this specification disclose certain specific details of the invention for the purpose of explanation of broader aspects f in en ion; but it is understood that details may. :be modified in various respects Without departure from the principles of the invention and that the invention may he applied to other structures than the one shown.

Referring to the drawings, the blank A in Figure 1 may be out and scored in multiple from rolls .or sheets of board, corrugated board, or other flexible sheet material. Only one side of the board need be imprinted or otherwise .deeoratively finished, since only one side of the blank is exposed to view, except for the inner bottom surface. In Figure 1 the blank is shown in the position in which the unfinished surface faces .the observer.

The blank is subdivided into panels and flaps by a plurality of fold lines. A bottom panel 11 is bordered by outer side fold lines 12 and 13 and outer end fold lines 14 and 15. These fold lines intersect at the corners 16, 17, 18 and 19 of the main panel which, as will later be seen, become the outer corners of the box.

Outer side wall panels 20 and 21 are articulated to the main panel 11 along the outer side fold lines 12 and 13, respectively. Inner side wall panels 22 and 23 are articulated to the outer side wall panels along side ridge fold lines 24 and '25. Side bottom flaps 26 and 27 are articulated to the inner side wall panels 22 and 23 along inner side fold lines 28 and 29, respectively.

In a similar manner outer end wall panels 30 and 31 are articulated to the main panel 11 along the outer end fold lines 14 and 15, respectively. Inner end Wall panels 32 and 33 are articulated to the outer end wall panels along end ridge fold lines 34 and 35, respectively. End bottom flaps 36 and 37 are articulated to the inner end wall panels 32 and 33 along inner end fold lines 38 and 39, respectively.

A pair of end corner flaps 40 and 41 are articulated to the outer end wall panel 30 along slanted fold lines 42 and 43 extending at an angle with respect to the outer end fold line 14. A further pair of end corner flaps 44 and 45 is articulated to the outer end wall panel 31 along slanted fold lines 46 and 47, respectively.

The corner structure of the blank includes at least two panel portions bordered by at least three corner fold lines aimed at a common point of intersection on the side ridge fold lines. In the illustrated form of blank substantially triangular panel portions 48 and 49 are articulated to the inner side wall panel 22 along inner corner fold lines 50 and 51, respectively. These fold lines intersect the side ridge fold line 24 at 52 and 53. Side corner flaps 54 and 55 are articulated to the outer side wall panel 20 along slanted fold lines 56 and 57, respectively. It will be noted that thesefold lines 56 and 57 are also aimed at the points of intersection 52 and 53, respectively. The side corner flaps 54 and 55 are further bordered by corner fold lines 58 and 59 towards the panel portions 48 and 49, respec-' tively. The corner fold lines 58 and 59 are also aimed at the points 52 and 53, respectively.

' Securing flaps 60 and 61 are articulated to the side corner flaps 54 and 55 along radial fold lines 62 and 63, respectively.

In a similar manner substantially triangular panel portions 68 and 69 are articulated to the inner side wall panel along inner corner fold lines 70 and 71, respectively. These fold lines intersect the side ridge fold line 25 at 72 and 73, respectively. A pair of side corner flaps 74 and 75. is articulated to the outer side wall panel 21 along slanted fold lines 76 and 77, respectively. 'It will be noted that these corner fold lines 76 and 77 are also med a h R M f ntersection 7.2m 7 r spe i ely- The Si ne flaps 4 and 75 a e further bordered by prne d n s 73 nd t va dsv the P nel portions 68 and 69, respectively. The corner fold lines 78 and 79 are also aimed at the points 72 and 73, respectively.

Securing flaps 80 and 81 are articulated to the side corner flaps 74 and 75 along radial fold lines 82 and 83, respectively.

Optional cuts 84, 85, 86 and 87 provide tabs 88, 89, 90 and 91. These tabs, when deflected, expose apertures through which the side bottom flaps are accessible during assembly of the carton.

The assembly of the blank A shown in Figure 1 into box form may proceed as follows:

It is advisable, particularly when heavy caliper board is used, to prebrea'k scores 24, 25 and 14 and 15.

Adhesive a is then applied to the securing flaps 60, 61, 80 and 81.

As a first folding operation, the side botom flaps 26 and 27 are folded upon the inner side wall panels 22 and 23 along the inner side fold lines 28 and 29, respectively.

The side wall assemblies are then folded over the inside surface of thebottom panel 11 along the outer side fold lines 12 and 13, respectively. The aforedescribed folding operations produce what is called in the art a compound fold and bring the securing flaps 60, 61, 80 and 81 into overlying position with respect to the outer end wall panels 30 and 31. The securing flaps 60 and 80 are then pressed into adhesive engagement with the outer end wall panel 30, and the securing flaps 61 and 81 are adhesively secured to the outer end wall panel 31.

Figure 2 illustrates the box blank in folded condition, the "blank being designated as A.

Next, adhesive may be applied to the end corner flaps 40, 41, 44 and 45 and the flaps are folded over the res'pective securing flaps 6t}, 86, 61 and 81, respectively. Application of adhesive to the corner flaps 40, 41, 44 and 45 is optional, but not necessary. After performance of the folding of the securing flaps, the blank has the appearance as shown in Figure 3, the blank being designated as A".

The blank A" may be shipped and stored in fiat collapsed condition and requires a minimum of space for shipping and storing. It may easily be set up into hollow box form by a simple operation which is illustrated in Fig. 4 and which will now be described.

In order to'erect the box, the end wall assemblies are folded at the fold lines 14 and 15 with respect to the bottom panel 11, while maintaining the side bottom fiaps substantially in contact with the bottom panel. This folding operation causes the inner edges 28 and 29 to recede towards the outer side edges 12 and 13 of the box and the side walls to assume hollow triangular crosssectional shape. The movement of the edges 28 and 29 is indicated by the arrows 96 and 97 Alternatively the inner edges 28 and 29 may be moved towards the outer side edges in the direction of the arrows 9 6.and'97. This causes the outer end panels 38 and 31 to rise automatically. I

It is seen that the blank folds at the radial fold lines 62, 82, 63 and 83, as Well as at the inner corner fold lines 50, '51, 70 and 71, respectively. In order to reduce the resistance of-the board to folding at these fold lines, the board may be interruptedly cut to weaken it.

'The points of intersection 52, 53, 72 and 73 rise as peaks and form four ridge corners. The side corner flaps 54, 55, 74 and 75 form end surfaces over which the uter end wall panels 30 and 31 are foldable and against which the end panels rest together with the flaps 40, 60, 41, .80 and the flaps 44, 61 and 45, 81, which are secured together and overlie the outer end wall panels 39 and 31, respectively.

When the folding of the outer end wall panels 30 and 31 is completed, the end ridge fold lines 34 and 35 extend between the peaks 52, 72 and 53, 73, respectively.

In O der to complete the setting up of'the box it is only necessary to fold the inner end 'wall panels 32 and 33 into their required position with respect to the main panel 11, and to tuck the end bottom flaps 36 and 37 into the interior space of the hollow end wall structures thus formed. The end bottom flaps have frictional engagement with the edges 98 and 99 shown in Figure 6.

In order to insure that the inner side flaps 26 and 27 lie flat on the bottom panel, the assembler, or an element of the assembling machine, may reach through the apertures in the inner side walls formed by deflection of the tabs 88, 89, 90 and 91 to push the inner side flaps down, if necessary.

With this background of the construction of the box, it will be easy to follow the method of calculating and delineating the blank instead of resorting to cut-and-try procedure as will now be described.

When a box for a particular purpose is to be constructed, the inner length and inner width of the box, as well as its height are first determined. Next, the most appropriate slope angles for the side walls and for the end walls are selected. These four data are sufficient for determining the size and shape of all the panels of the blank including the triangular segments at the corners which invariably turn out accurately, with regard to all dimensions, if calculated and drafted as follows:

Referring to Figure 1, the outline of the inner bottom area is first drawn as a rectangle consisting of the lines 100, 101, 102 and 103. These are the lines on which the inner side fold lines 28, 29 and the inner end fold lines.38, 39 come to rest in the finished box.

Next, cross-sectional diagrams of an end wall and of a side wall of the box are drawn. In actual practice it is not necessary to draw the thickness of the several panels as double lines as is done in Figures 7 and 8 but it is quite sufficient, and even preferable to draw these, most particularly the triangular portions, in single lines as indicated by the broken lines of these figures.

In drawing each of these simple cross-sectional diagrams, first two parallel horizontal lines 24 and 100 or 34 and 102 are drawn, spaced apart the known height H of the vertical inner walls of the box. Next, across these parallel lines is drawn a sloping line 30 or 21 at the predetermined angle ES or SS of the respective sloping outer wall. And finally, a vertical line 32 or 23 is drawn through the point where the sloping line intersects the upper horizontal line. This procedure produces rightangled triangles which yield the dimension EW of the outer end walls 30 and 31 and the dimension SW of the outer side walls 20 and 21. Furthermore, the dimensions EF and SF are obtained. These are the distance by which the bottom panel 11 of the box extends beyond the ends and sides respectively of the inner bottom area defined by the lines 100, 101, 102 and 103 of Figure 1. These dimensions,'as will later appear, are also the appropriate depths respectively, of the end bottom flaps 36 and 37 and of the side bottom flaps 26 and 27.

Returning from the cross-sectional diagrams Figure 7 and Figure 8 to the layout of the blank of Figure 1 it is now possible to draw the outer side fold lines 12 and 13 parallel to the lines 100 and 101, at a distance SF therefrom. Similarly, it is possible to draw the outer end fold lines 14 and 15 parallel to the lines 102 and 103 at a distance EF therefrom. The resulting rectangle has corners 16, 17, 18 and 19 and constitutes the actual bottom panel of the box.

It is apparent that the spacing of the lines 100 and 101 determines the length EL of the inner end panels 32 and 33, later to be drawn. Similarly, the spacing of the lines 102 and 103 determines the length of the inner side panels 22 and 23.

The dimension SW is obtained from the cross-sectional diagram Figure 8 permitting drawing of the side ridge fold lines 24 and 25. Similarly the dimension EW is obtained from the cross-sectional diagram Figure 7 and permits the drawing of the end ridge fold lines 34 and 35.

The points 52, 53, 72 and 73 are obtained as intersections of the lines 102 and 103 with the side ridge fold lines 24 and 25. It is now possible to draw the lines 56, 57, 76 and 77 connecting the corner points 16, 17, 19 and 18 with the points 52, 53, 72 and 73. These lines include equal angles S between the side fold lines 12 and 13 and the slanted side edges 56, 57, 76 and 77 of the outer side wall panels 20 and 21.

The length of the end ridge fold lines 34 and 35 is fixed by the spacing of lines and 101. It is then possible to draw line 42, 43, 46 and 47 which are the slanted side ridges of the outer end wall panels 30 and 31. These lines lead from the intersection of the lines 34 and 35 with the lines 100 and 101 to the corners 16, 17, 19 and 18. The lines 42, 43, 46 and 47 include equal angles E with the end fold lines 14 and 15.

Next it is necessary to find the direction of the radial fold lines 62, 63, 82 and 83. This may be done in two ways, by measurement and computation or by drafting, as follows:

Taking up first the process of computation, the angles E and S are measured. Assuming, for example, that the angle E is 67.5 degrees and that the angle S is 40.5 de grees, the computation proceeds as follows: 67 .5 is added to the corner angle of the bottom panel which is 90 degrees, making a total of 157.5 degrees. From this is subtracted the angle S being 40.5 degrees leaving a balance of 117 degrees. This figure is divided by 2 giving an angle of 58.5 degrees, which is the size of the angle R for the radial fold lines 62, 63, 82 and 83 and these lines may now be drawn.

The graphic determination of the angle R is illustrated at the upper right hand corner of the blank, Figure 1, the procedure at the other corners being the same.

The angle E is added to the line 76 at 19 producing a hypothetical line 108, including an angle C with the straight extension of the outer end fold line 14. The angle C is then divided into equal halves to establish the direction of the radial fold line 82.

The hypothetical line 108 also yields the point of intersection 106 on the straight extension of the inner side fold line 29 to which it is now possible to draw the line 78 from 72 and similarly to draw the lines 58, 59 and 79 to the points 104, and 107 at the other corners of the blank.

The outline of the end corner flaps 40, 41, 44 and 45 is optional and not critical, since it is obviously only necessary to lay out their bordering edges, so that they will not interfere with the folding of the blank. This is easily apparent from a consideration of Figure 3.

Blanks calculated and produced according to the invention are readily folded and glued on standard highspeed folding box machines. They are quickly and easily set up from flat, collapsed condition, either manually or mechanically, and invariably result in a neat box in which the corners are accurate and free from stress, a result which is most difiicult to obtain by the out-and-try method particularly if the slope angles for the side walls and the end walls are unequal.

The above given figures apply to a box having a slope angle of 55 degrees for the side walls, and 35 degrees for the end walls. It is, of course, possible to select any other slope angles, equal or unequal for the side walls and for the end walls. By following the aforedescribed procedure of calculating and drafting the blank, all dimensions of the box are accurately obtained and the angles, length and width of the panels and flaps are determined with definite accuracy, so that in folding the blank the corners miter neatly, no bulges or dimples occur, and a box is obtained which is very strong and free from internal stresses.

What is claimed is:

1. A blank for forming a hollow walled folding box having walls of triangular cross-section comprising a botpanel along an outer side bottom fold line, an inner side wall panel hinged to the outer side wall panel along a side ridge fold line, and a side bottom flap articulated to the inner side wall panel along an inner side bottom fold line; an outer end wall panel articulated to the bottom panel along an outer end fold line, an inner end wall panel articulated to the outer end wall panel along an end ridge fold line, and an end bottom flap articulated to the inner end wall panel along an inner end fold line, said inner wall panels being of substantially equal height, the outer side wall panel having a slanted side edge along which a side corner flap is articulated, the outer end wall panel having a slanted side. edge along which an end corner flap is articulated, the side corner flap being bordered by a radial fold line extending to the corner of the bottom panel, a securing flap articulated to the side corner flap along said radial fold line, said end corner flap being adapted to be secured to said securing flap before setting up of the blank into hollow box form characterized in that the angle R between the radial fold line and the tapered side edge of the outer side wall panel equals one half of the total obtained by first adding to the corner angle of the bottom panel the angle included, in the flat blank, between the tapered side edge of the outer end wall and the outer end fold line, and then subtracting from the added angles the angle included between the tapered side edge of the outer side wall panel and the outer side fold line.

2. Corner construction for a hollow walled folding box having walls of triangular cross-section comprising a bottom panel; an outer side wall panel hinged to the bottom panel along an outer side bottom fold line, an inner side wall panel hinged to the outer side wall panel along a side ridge fold line, and a side bottom flap articulated to the inner side wall panel along an inner side bottom fold line; an outer end wall panel articulated to the bottom panel along an outer end fold line, an inner end wall panel articulated to the outer end wall panel along an end ridge fold line, and an end bottom flap articulated to the inner end wall panel along an inner end fold line, said inner wall panels being of substantially equal height, the outer side wall panel having a slanted side edge along which a side corner flap is articulated, the outer end wall panel having a slanted side edge along which an end corner flap is articulated, the side corner flap being bordered by a radial fold line extending to the corner of the bottom panel, a securing flap articulated to the side corner flap along said radial fold line, said end corner flap being adapted to be secured to said securing flap be fore setting up of the blank into hollow box form characterized by a layout of the flat blank in which the said radial fold line bisects the angle between a hypothetical,

extension of the outer end fold line and a hypothetical line obtained by adding to the slanted side edge of the outer side wall panel an angle equal to the angle between the outer end fold line and the slanted side edge of the outer end wall panel, the vertex of the added angle being at the corner of the bottom panel.

3. Corner construction for a hollow walled folding box having walls of triangular cross-section comprising a bottom panel; an outer side Wall panel hinged to the bottom panel along an outer side bottom fold line, an inner side wall panel hinged to the outer side wall panel along a side ridge fold line, and a side bottom flap articulated to the inner side wall panel along an inner side bottom fold line; an outer end wall panel articulated to the bottom panel along an outer end fold line, an inner end wall panel articulated to the outer end wall panel along an end ridge fold line, and an end bottom flap articulated to the inner end wall panel along an inner end fold line, said inner wall panels being of substantially equal height, the outer side wall panel having a slanted side edge along which a side corner flap is articulated, the outer end wall panel having a slanted side edge along which an end corner flap is articulated, the side comer flap being bordered by a radial fold line extending to the corner of the bottom panel, a securing flap articulated to the side corner flap along said radial fold line, said end corner flap being adapted to be secured to said securing flap before setting up of the blank into hollow box form characterized by a layout of the flat blank in which the said radial fold line bisects the angle between a hypothetical extension of the outer end fold line and a hypothetical line obtained by adding to the slanted side edge of the outer side wall panel an angle equal to the angle between the outer end fold line and the slanted side edge of the outer end wall panel, the vertex of the added angle being at the corner of the bottom panel, said side corner flap being a triangle whose sides are said slanted side edge of the outer side wall panel, said radial fold line, and a line extending from the intersection of said last named slanted side edge with the side ridge fold line to the intersection of said radial fold line with a straight extension of the inner side bottom fold line, in the fiat blank.

References Cited in the file of this patent UNITED STATES PATENTS 2,519,831 Frankenstein Aug. 22, 1950 2,531,255 Clarke Nov. 21, 1950 2,605,953 Williamson Aug. 5, 1952 2,605,954 Williamson Aug. 5, 1952 

